It begins in a provocative way, not in a rude and attacking way. It is possible to be one and not the other; if the poster chooses to be both provocative and rude, or opts toward simply being rude, then the fault lies solely on the poster.
I wonder how many authors and posters clothe their attacks in provocative, even incendiary statements? Could it be that someone accustomed to such tactics might react badly to a provocative post where no ill was intended?
That doesn’t excuse bad behavior, but might raise the awareness of one intending to post.